C socket get IP address from filedescriptor returned from accept
Ok. Thanks to @alk and @rileyberton I found the correct method to use, the getpeername:
int sockfd;void main(void) { //[...] struct sockaddr_in clientaddr; socklen_t clientaddr_size = sizeof(clientaddr); int newfd = accept(sockfd, (struct sockaddr *)&clientaddr, &clientaddr_size); //fork() and other code foo(newfd); //[...]}void foo(int newfd) { //[...] struct sockaddr_in addr; socklen_t addr_size = sizeof(struct sockaddr_in); int res = getpeername(newfd, (struct sockaddr *)&addr, &addr_size); char *clientip = new char[20]; strcpy(clientip, inet_ntoa(addr.sin_addr)); //[...]}
So now in a different process I can get the IP address (in the "string" clientip
) of the client that originated the connection only carrying the file descriptor newfd
obtained with the accept method.
You would use getsockname()
(http://linux.die.net/man/2/getsockname) to get the IP of the bound socket.
Also answered before, here: C - Public IP from file descriptor
Statefull connection is uniquely identified by two end points Peer(address:port)<=>My(address:port). Both getpeername() and getsockname() are needed to get this information.